THE LAW OF SUBSTANCE. 225 



a dislike of strain ; they strive after the one and 

 struggle against the other. 



II. — There is no such thing as empty space ; that 

 part of space which is not occupied with ponderable 

 atoms is filled with ether. 



III. — There is no such thing as an action at a 

 distance through perfectly empty space ; all action of 

 bodies upon each other is either determined by 

 immediate contact or is effected by the mediation of 

 ether. 



Both the theories of substance which we have just 

 contrasted are monistic in principle, since the opposi- 

 tion between the two conditions of substance — mass 

 and ether — is not original ; moreover, they involve a 

 continuous immediate contact and reciprocal action of 

 the two elements. It is otherwise with the dualistic 

 theories of substance which still obtain in the idealist 

 and spiritualist philosophy, and which have the 

 support of a powerful theology, in so far as theology 

 indulges in such metaphysical speculations. These 

 theories draw a distinction between two entirely 

 different kinds of substance, material and immaterial. 

 Material substance enters into the composition of the 

 bodies which are the object of physics and chemistry ; 

 the law of the persistence of matter and force is 

 confined to this world (apart from a belief in its 

 "creation from nothing" and other miracles). 

 Immaterial substance is found in the " spiritual 

 world " to which the law does not extend ; in this 

 province the laws of physics and chemistry are either 

 entirely inapplicable or they are subordinated to a 

 "vital force," or a "free will," or a "divine omni- 

 potence," or some other phantom which is beyond 

 the ken of critical science. In truth, these profound 



Q 



